1. Field of the Invention
This invention relates to dispensing containers and more particularly to that class utilizing deformable walls.
2. Description of the Prior Art
The prior art abounds with containers adapted to dispense semisolid materials. U.S. Pat. No. 381,553 issued Apr. 24, 1888 to C. H. Hollis teaches a cylindrical hollow container having a dispensing port at one end and a manually positioned slidable piston element located within the interior of the container, accessible at the other end thereof. Packing insures a tight fit between the marginal edges of the piston and the interior walls of the container. A cap is removably secured to the container covering the dispensing opening therein.
U.S. Pat. No. 3,595,449 issued on July 27, 1971 to P. W. Stump discloses a plastic piston and tubular container for dispensing semisolids, such as ice cream and the like. The piston has a flat, flexible, obturating wall; a depending peripheral skirt or flange, proportioned to guide the piston axially along the tubular container, with a flared lower edge to provide a fluidtight seal; and a central tubular hub, corrugated to provide radial flexibility, for connecting either a rodlike or tubular push device to the piston.
Both of the aforementioned patents suffer the common deficiency of relying upon a fluid-tight fit between the periphery of the piston and the interior walls of the container. This requires such containers to be fabricated with great accuracy and to possess substantial rigid characteristics above and beyond that utilized in deformable containers such as toothpaste squeeze type dispensing apparatus.